This invention relates to electronic communication systems, and more particularly to a system and method for providing network connections between devices on a printed circuit board.
The IEEE 802.3 specification is one example of a network communication protocol allowing a plurality of different computer devices to communicate over a local area network (xe2x80x9cLANxe2x80x9d) connected by copper wire cabling. Originally, IEEE 802.3 specified the use of 50 ohm coaxial cable of 0.4 inch diameter carrying data at rates up to 10 Mbps, which became know as 10Base5 cabling or xe2x80x9cthickxe2x80x9d ethernet. Thick ethernet, however, proved expensive and inflexible for a number of smaller network applications. Subsequently, a number of lower cost variations of the basic thick ethernet protocol has been provided. As recommended by a number of new standards, various different types of cabling have been used such as 10Base2 cabling or xe2x80x9cthinxe2x80x9d ethernet and even and ordinary unshielded twisted pair wiring (xe2x80x9cUTPxe2x80x9d) which is known as 10Base-T ethernet. In other embodiments, 100 Base-T also works on UTP.
Each of these different flavors of network protocols is designed to allow computing devices to connect and communicate over different physical distances. Thick ethernet cabling allows runs to connect machines separated up to 500 meters, where thin ethernet allows cable runs up to 200 meters and 10base-T and 100 Base-T ethernet allows cable runs 100 meters from the hub.
With computer LANs becoming more widespread, the use of network protocols has greatly increased as well and are now widely utilized for a variety of various LAN applications. To date, however, ethernet protocols have been largely utilized to connected different computing devices over a length of cable or copper wiring. As the level of integration of electronic devices continues to increase and the size of computing devices continues to decrease, network protocols may find a number of new applications.
According to the embodiments of the present invention, the ability to utilize networking protocols to communicate between different electronic devices is significantly extended. The present embodiment allows networking protocols to be implemented over different types of physical transmission medium.
In a particular embodiment, a network protocol connection can be implemented between electronic devices situated on the same printed circuit board (xe2x80x9cPCBxe2x80x9d) over a physical communication medium on the PCB board. In this embodiment, electronic devices situated closely together on the same PCB can communicate using a network communication protocol such as ethernet 10/100Base-T network protocols originally designed to provide communications in a local area network. The physical communication medium may include conductive traces etched onto a PCB.
According to an exemplary embodiment of the invention, a matching network is utilized to interface a Medium Access Control (MAC) block providing network protocol functions to the physical communication layer of the PCB. In the exemplary embodiment, the matching network enables the MAC block to implement a network protocol connection on the physical communication medium of a PCB. The matching network provides isolation and the proper electrical characteristics to interface with and implement networking protocols on the particular communication medium. For example, the matching networks isolate and electrically match the characteristic impedance of the differential traces etched on a PCB.
According to another aspect of the invention, a hub device provides communications between a plurality of electronic devices on a PCB using a networking protocol. The hub allows a greater number of devices to access and communicate over a shared physical communication medium. In an exemplary embodiment, a collision detect block indicates when more than one device is attempting to transmit on the shared communication medium to arbitrate access between a plurality of device communicating on the shared medium.
According to yet another aspect of the invention, the need for a repeater and repeater state machine is eliminated. Implementing local area network protocols on a PCB reduces the distance between networked devices and signal propagation delays, eliminating the need for the repeater and repeater state machines normally necessary for handling signals travelling over greater physical distances.
The present invention extends the use of local area networking protocols, such as the ethernet protocol. In the illustrative embodiments, networking protocols can be implemented between smaller electronic devices situated closely on a printed circuit board. Simplification of the electronic circuitry required to implement networking protocols allow easier and more inexpensive communication between electronic devices. This also allows the use of existing off-the-shelf integrated circuits to be used such that the product development cycle is reduced. Wider use of network protocols allows easier implementation of communication between devices as integration of electronic devices continues to increase.
The foregoing and other features and advantages of preferred embodiments of the present invention will be more readily apparent from the following detailed description. The detailed description proceeds with references to the accompanying drawings.